C1571 Code - Vehicle Speed Signal Malfunction
Quick Answer
The diagnostic trouble code C1571 indicates a Vehicle Speed Signal Malfunction. Common causes include Faulty speed sensor: The most common cause of a vehicle speed signal malfunction is a faulty speed sensor, Over time, the sensor can wear out or become damaged, leading to inaccurate readings or a complete failure, Wiring issues: Problems with the wiring harness connecting the speed sensor to the ECM can also cause this code to trigger. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- C1571 indicates Vehicle Speed Signal Malfunction.
- Common causes
- Common causes include Faulty speed sensor: The most common cause of a vehicle speed signal malfunction is a faulty speed sensor, Over time, the sensor can wear out or become damaged, leading to inaccurate readings or a complete failure, Wiring issues: Problems with the wiring harness connecting the speed sensor to the ECM can also cause this code to trigger.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code C1571 Description
The diagnostic trouble code C1571 indicates a Vehicle Speed Signal Malfunction. This code is typically associated with issues related to the vehicle's speed sensor or the circuit that transmits the speed signal to the vehicle's computer system. The vehicle speed signal is crucial for various systems in the vehicle to function correctly, including the transmission, ABS, traction control, and cruise control systems. When this signal malfunctions, it can lead to a range of performance issues and potential safety concerns.
Common Causes of C1571
- Faulty speed sensor: The most common cause of a vehicle speed signal malfunction is a faulty speed sensor. Over time, the sensor can wear out or become damaged, leading to inaccurate readings or a complete failure.
- Wiring issues: Problems with the wiring harness connecting the speed sensor to the ECM can also cause this code to trigger. Broken wires, loose connections, or corrosion can disrupt the signal transmission.
- Sensor alignment: If the speed sensor is not properly aligned or positioned, it may not be able to accurately detect the vehicle's speed, leading to signal malfunctions.
- ECM issues: In rare cases, a malfunctioning ECM or other control module could be causing the vehicle speed signal malfunction. This would require further diagnosis and potentially replacement of the faulty module.
- Vehicle speed signal interference: External factors such as electromagnetic interference or other signals can interfere with the vehicle speed signal, causing inaccuracies or disruptions.
Symptoms of C1571
- Inaccurate speedometer readings: One of the most common symptoms of a vehicle speed signal malfunction is an inaccurate speedometer reading. The speedometer may show speeds that are higher or lower than the actual speed of the vehicle.
- ABS or traction control warning light: A malfunctioning speed sensor can trigger the ABS or traction control warning lights on the dashboard. This indicates that the systems relying on the speed signal are not functioning properly.
- Erratic shifting: The vehicle's transmission may experience erratic shifting patterns or delays in shifting due to incorrect speed information being received.
- Cruise control issues: A faulty speed sensor can cause problems with the vehicle's cruise control system, leading to difficulties in maintaining a set speed.
- Loss of power: In some cases, a malfunctioning speed signal can result in a loss of power or acceleration, as the ECM may not be able to adjust engine parameters effectively.
How to Fix C1571
- Diagnose the issue: The first step in resolving a vehicle speed signal malfunction is to diagnose the specific cause of the problem. This may involve using a diagnostic scanner to retrieve the trouble codes and conducting a visual inspection of the speed sensor and wiring.
- Replace the speed sensor: If the speed sensor is found to be faulty, it will need to be replaced. The sensor is typically located on the transmission or wheel hub, depending on the vehicle make and model.
- Check wiring and connections: Inspect the wiring harness for any damage, corrosion, or loose connections. Repair or replace any damaged wires and ensure that all connections are secure.
- Clear codes and test drive: Once the repairs are completed, clear the trouble codes from the vehicle's computer system and test drive the vehicle to ensure that the issue has been resolved.
- Relearn procedure: In some cases, a relearn procedure may be required to recalibrate the ECM or other control modules with the new speed sensor. This can typically be done using a diagnostic scanner.
Cost to Fix C1571
The cost of repairing a vehicle speed signal malfunction can vary depending on the specific cause of the issue and the make and model of the vehicle. In general, replacing a faulty speed sensor can cost between $100 and $300 for the part, with additional labor costs of $100 to $200. If wiring repairs or ECM replacement are necessary, the total repair cost could be higher.
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Code C1571 Information for Specific Makes
- C1571 Lexus — Vehicle Speed Signal Malfunction
- C1571 Scion — Vehicle Speed Signal Malfunction
- C1571 Toyota — Vehicle Speed Signal Malfunction
Frequently Asked Questions about C1571 Code
1. What does OBDII code C1571 mean?
C1571 indicates a Vehicle Speed Signal Malfunction, meaning the vehicle's control module is not receiving a proper speed signal or the signal is corrupted.
2. What are the common symptoms of code C1571?
Symptoms can include an illuminated check engine light, malfunctioning speedometer, ABS or traction control warnings, and erratic transmission shifting.
3. What causes a C1571 Vehicle Speed Signal Malfunction?
Common causes include a faulty vehicle speed sensor (VSS), damaged wiring or connectors, a malfunctioning ABS module, or issues with the powertrain control module (PCM).
4. How is code C1571 diagnosed?
A technician will check the vehicle speed sensor, inspect wiring and connectors for damage, and use a scan tool to monitor speed signal data to locate the fault.
5. Can I drive with code C1571 active?
Driving with C1571 may be possible, but it is not recommended, as issues like erratic shifting and impaired ABS or traction control can compromise safety.
6. How do you fix the C1571 code?
Repairs may involve replacing the vehicle speed sensor, repairing damaged wiring, cleaning or reconnecting corroded connectors, or reprogramming the PCM or ABS module if needed.
7. How much does it cost to repair code C1571?
Repair costs can vary, but replacing a vehicle speed sensor typically ranges from $100 to $250, while wiring repairs or module reprogramming may cost more.
8. Can a faulty ABS module trigger code C1571?
Yes, a malfunctioning ABS module can interfere with the vehicle speed signal, leading to the C1571 code.
9. What tools are needed to fix a C1571 code?
Common tools include an OBDII scanner, a multimeter for testing wiring and sensors, and sometimes specialized diagnostic equipment for module reprogramming.
10. Will clearing the C1571 code fix the problem?
Clearing the code will erase it temporarily, but if the underlying issue is not resolved, the code will likely return.
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